In healthcare, patient outcomes are dependent not only on the skills of individual practitioners, but also on their skills in working as a team. These skills are particularly evident in multi-disciplinary teams such as operating room, critical care, emergency department, and trauma teams, among which knowledge must be shared and coordinated across specialties in a time-critical setting. In trauma resuscitation, the team starts with an initial plan based on Advanced Trauma Life Support (ATLS), but may not be able to execute the plan as initially envisioned due to unexpected or non-routine events. It is widely recognized that team coordination can suffer during this type of unexpected situation and that these breakdowns are often implicated in adverse events. Research in other complex high risk industries has shown that the most predictive factor of effective team performance in crisis situations is the team's ability to appropriately adapt coordination activities to meet situational requirements. In this study, we seek to indentify optimal adaptive coordination patterns within multidisciplinary teams during trauma resuscitation. The proposed work will provide an assessment of team coordination in trauma resuscitation, a time-critical medical setting in both adult and pediatric patient populations. Using hierarchical task analysis, coordination requirements during trauma resuscitation will be determined. Observations will then be used to assess coordination in routine and non-routine work using a validated observation tool. Finally, observations will again be used to identify differences in coordination between high- and low-performing teams. At the end of this project, coordination requirements of trauma teams during resuscitation will be identified, optimal coordination patterns for each stage of the resuscitation and during non-routine events will be determined, and the relationship between coordination and process measures will be discovered. This project will result in improved coordination during trauma resuscitation, providing essential knowledge for trauma teams but with generalizability to other time-critical medical settings.